A vehicular seat coupling is described in European patent No. 9,2403,299 which discloses a vehicle seat having a mechanism to attach the seat to the floor, which has a latch with a protrusion movably mounted from the seat, for insertion in an opening in the floor. When unlocked the latch can intrude into or be withdrawn from the opening, and when locked the latch protrusion is supported on and locked under an edge of the opening. A drawback of this prior art structure is that the locking latch is the member that attaches the seat to the floor when in use and it must therefore endure all the stresses generated on the seat.
Another device, described in European patent No. 9,302,490, is a system for quick mounting/dismounting of seats or other accessories having two bolts interlocked by articulation. Each bolt extends into a catch and when an actuating handle is pulled upwardly the respective catches retract and can cross a window in a base plate that is attachable to the floor, and when the handle is pushed down, the respective catches move away from each other and are locked against the underside of the platform.
The drawback of these known mechanisms is that when the latch or latches are not in the locked position, the seat is not attached to the floor and can be removed from its position, moreover the seat will not be anchored and serious accidents can occur when the latch is accidentally actuated while the vehicle is moving.
Since the anchoring of the seat in the known structures is carried out with movable parts, there is frequently a play between them, resulting in annoying noises in a moving vehicle.